This invention relates to the field of implantable electromedical devices. In particular, it relates to an implantable electromedical device having a replaceable power supply module.
Implantable electromedical devices such as cardiac pacemakers have been known and commercially used for many years. In time, the power supply depletes and the entire pacemaker system, consisting of a power supply module and electronic stimulating signal generating module, is replaced. There are several advantages to be obtained in simply replacing the depleted power supply. One is the cost savings in retaining the original signal generating module. Another is the convenience and minimization of risk which results from not having to disturb the implanted signal generating module and its associated leads connected to the tissue to be stimulated. A third is flexibility in instrumentation afforded by replacing one power supply with another of a different type should the patient's requirements change.
While the general concept of a replaceable power supply for electromedical devices is not new, there is a significant barrier to its adaptation to the field of implantable electromedical devices. This barrier is the result of the hostile environment presented by electrolytic body fluids. These conductive fluids inevitably infiltrate the junction between the power supply and signal generating modules, permitting current leakage from the power supply via the connector pins or other means for electrically joining the two modules. This current leakage substantially reduces the active life of the device as well as corrode the connector pins.